IB HL Physics 2025-32 - E3. Radioactive decay

E3. Radioactive decay

Why are some isotopes more stable than others?

In what ways can a nucleus undergo change?

How do large, unstable nuclei become more stable?

How can the random nature of radioactive decay allow for predictions to be made?

Are there differences between the photons emitted as a result of atomic versus nuclear transitions?
How does equilibrium within a star compare to stability within the nucleus of an atom?
Would a nucleus be able to exist if only gravitational and electric forces were considered?
How did conservation lead to experimental evidence of the neutrino? (NOS)
Which areas of physics involve exponential change? (NOS)

isotopes
nuclear binding energy and mass defect
the variation of the binding energy per nucleon with nucleon number
the mass-energy equivalence as given by E = mc2 in nuclear reactions
the existence of the strong nuclear force, a short-range, attractive force between nucleons
the random and spontaneous nature of radioactive decay
the changes in the state of the nucleus following alpha, beta and gamma radioactive decay
the radioactive decay equations involving α, β − , β + , γ
the existence of neutrinos and antineutrinos
the penetration and ionizing ability of alpha particles, beta particles and gamma rays
the activity, count rate and half-life in radioactive decay
the changes in activity and count rate during radioactive decay using integer values of half-life
the effect of background radiation on count rate.
the evidence for the strong nuclear force
the role of the ratio of neutrons to protons for the stability of nuclides
the approximate constancy of binding energy curve above a nucleon number of 60
that the spectrum of alpha and gamma radiations provides evidence for discrete nuclear energy levels
the continuous spectrum of beta decay as evidence for the neutrino
the decay constant λ and the radioactive decay law
that the decay constant approximates the probability of decay in unit time only in the limit of sufficiently small λt
the activity as the rate of decay
the relationship between half-life and the decay constant.

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